Pleochroic television process and apparatus



March 16, 1954 A. WRIGHT PLEOCHROIC TELEVISION PROCESS AND APPARATUS Filed March 24, 195o 2 Sheets-Sheet l A. WRIGHT March 16, 1954 PLEocHRoIc TELEVISION PRocass AND APPARATUS 2 shets-sheet 2 Filed March 24, 1950 w .gli cq zzuml Q INVENTOR Own;

nzOOmm Patented Mar. 16, 1954 PLEOCHRGIC TELEVISION PROCESS AND .APPARATUS Arthur Wright,` Forest Hi William E. Celestin,

lls, Y., assignorto New '.York, Y.

. Application March.24, 1950, .Serial ,No..151,711

l Claim. (Cl. 340-369) My invention relates particularly to a process and apparatus for transmitting 'and receiving visual images electronically.

A-n yobject of my invention is toprovide .a process and apparatus for 'transmittingand receiving images in colorswhichfpreferably are natural and accurately reproduced. .This is accomplished in 'accordance with my invention, Eby dividing lthe images to be transmitted intolcomponents of the diiierent colors thereof which are individually transmitted and thereafter received by Ameans of electrical impulses which are translated by uorescence into light having components corresponding to those originally transmitted. The images thus produced by the visual blending' of said colors may be viewed either directly on the surface of the picture tubein which the images are received, or, if desired,` the `images may be viewed by optical projection onto another, dierent or larger lViewing surface or screen. A further object is to attain accuracy by 'having .incorporated in the apparatus accurately matched color lmosaic plates, both with the camera tube and with the picture tube or'kinescope.

Further objects of my invention will be apparent vfrom the detailed' description of .the same hereinafter.

While my invention is capable of .embodiment in many different forms, forthe purpose .of .illustration I have shownand described only -certain embodiments thereof :hereinafter in connection with the accompanying drawings, in which- Fig. 1 is a diagrammatic representation of an image orthicon tube, or other television camera tube, and the circuits which may be used-,therewith in sending or transmitting the video signa-ls of images to be reproducedat .the receiving end of the system;

Fig. 2 is a diagrammatic representation, venlarged, of a pleochroic mosaic color `plate used' with the camera tube, which may have. either `a iiat or curved light-receiving face;

Fig. 3 is a diagrammatic representation of the picture tube which'may have either a iiat or curved -viewing face, and the circuits rwhich may` be used therewithyand Fig. 4 is an elevation of a horizontally adjustable color mosaic screen which may, if desired, be located in front of .the picture tube.

Referring to the drawings, I have shown a color television vsystem'comprising `ascene I which is to be transmitted, an image of which is thrown by any desired objective 2 ontoxaphoto cathode 3, having on its right face innumerable `silvercesium photo-electric material particles,of Van image orthicon 4 or any other type of camera tube, the said orthicon being of-ithe well'known type except that on the outside'or inside'o'f the left Vlight receiving face eofithe tube #infront of the photo cathode 3, oronwthe left face of the photo cathode; thereis provided a microscopic color pattern mosaic *5. This maybe, preerablypcomprised fgeometrically of affserie'sfof parallel ansularly or .diasonallyslccatedeil ,lilies 6, between which therearelQcated a succession of alternating 'blue ,areas l and ,greenarcas 8, It will be noted that, preierablmany one .3-olor sequence ofred, .blue and greenareas vis `not hprizontal ibut inclined so as 'to ,be slightly higherE at either end, compared,totheinclination `of 4the usual electron scanning lines, `when viewingthe positions of the scanning lines and color .areas from the same viewpoint, .forms/tance ,from the outside of the tube il. The depths andshade .of color and areas of these colorelements .aresuch that, preferably, .together .they produce white light, although any .othercclors,mayhesused if desired.

'This color Ipattern for mosaic '5, .tllius ,has r`the separate vthree or more `color .areas 6, 1 r,and 8, which are .approximately lrectangiilar...in ,shape and which may be .produced .in anydesired ,way, for vinstance as in malingcolor .mosaic `photograph screen plates for .reproducing coloriirnages photographically. The individualcolprs h or pigments may be of anydesired andknown color.- ing materials, whether of ra.,mineral .or organic nature, as for instance coal .tar orsynthetc .dyestuifs, .or transparent mineral compounds `.such as those which may be made 'in producins Synthetic or artificial vgems,which are vgenerally silicates or oxides of aluminium or .other materials Aand which ofttimes carryfthe necessary Asmall proportions ofk mineralimpurities producingthe respective desired colors, yas ,inthe @case .of gems. If desired,.an adhesive or carrierfor the pigments may .b e used, ,Whichlis preferablyitransparent and colorless, as for iinstance-.aplastic or sodium silicate or potassium silicate. The-:color mosaic 5 is located o n the ..left.fface .o f, creas :near as possible to, ,the photo cathode 3 .withwhich it may be in Contact, 'if desiredon thefinner face of the glass wall of the orthiconorother camera tube t, or it may be on the outside of saidglass wall. When the color ,mosaic is .carriedon the left face ofthe .photo cathode 3 ftherefmay be applied theretoa l,protective `.layer or coating of any desired kind, as iorinstance ay 7thinfglassplate or sodium silicate .orpotassium.-.Silicate, V.which protects. and separatesthe trays, and ,ions .which may be present in the,evacuatedspacedn Athe tube .2 from contact .with the-.color mosaic 5. The respective Vdifferent color-.elements 16,- 'lfand may be vof any desired dimensions.vf.or.instance with a Width of 3 to 30per;irurrnnor..even,N a much greater width-.than salda to 30..perInmqify the received image is.not

The rlight received from thecolor patternf5 is thus receivedfbygthe'gphoto cathode `3 .and .as `.a result Lcorresponding-.elec-` trons are projected .onto a. targetplate l.. having the usual secondary-electron `;ollec,ting wire screen |0..1ocated in `front. thereof .so that-,the electrical image whichisfthusprqduced o right -side oigtheftarglplate i9 isiscannedgb enlarged by ipr'oiectioil mail f electron'scanning Ziaeam ^I'| "in Lthe -Ausual way,

3 transmitted through the camera tube 4 with the aid of a focussing coil I2, a deflection coil I3 and an alignment coil I4 so that the resultant variations in the current, after passing through a i'ivestage electron multiplier section i5, are transmitted to a broadcasting aerial I6 with the aid of any desired circuits I1 which may, for example, be arranged as provided in Grob, Basic Television, McGraw-Hill Book Company, 1949, and particularly page 513 thereof. The broadcast television signals are thence received by an aerial I8 and conveyed by any desired receiving set circuits I9, such for example as provided in Grob, ibid., and particularly page 128 thereof, to a kinescope or picture tube of any desired character, such for instance as one of those in Grob, ibid., on page 42 or page 128, or the flat faced picture tube such as on page 149 thereof. Said picture tube 20 has on the inner face or Wall thereof a layer or coating of any desired fluorescent material 2i, such for instance as. preferably, cadium tungstate which produces white light when acted upon by an electron scanning beam 22 oi said picture tube. Between the iiuorescent coating EI and the glass wall of the picture tube 2t, the color mosaic being thus protected, from the electrons and ions that may be present, by the fluorescent coating 2i, or on or associated with the front face or viewing surface of the picture tube 26, there is provided another color mosaic 23 constructed in substantially the same Way and with the same color pattern as described hereinabove, taking into account the relative sizes ci the image on the photo cathode 3 shown in Fig. 2, so that the color elements in the mosaic 23 will be larger or smaller than the color elements in the screen 5, according to the relative sizes of the photo cathode image and the picture tube image. If desired., this color mosaic 23 may be in the form of a movable screen, as shown in Fig. 4, in which the color mosaic is carried by any desired supporting layer 24, such for instance as of gelatine which is carried Within a slfnftable frame 25 having three guide rods 25, 21 and 28 slidably carried in brackets 23, 3i! and 3l supported by the television receiving set closely adjacent to the front of the picture tube 243. A fourth rod 32, with its inner end rotatably carried in the frame 25, is screw-threaded Within a similar supporting bracket 33, and has a rotatable thumb-serew head 34 thereon, so that by turning the head 34 the position of the screen 23 may be adjusted laterally across the face of the tube 29 to set or change the registry of the screen elements with the color picture elements transmitted from the camera tube.

In carrying out the operation of my process, the subject to be transmitted, for instance a stage scene, will be focussed by the objective 2 onto the photo cathode 3 through the color mosaic 5, .as a result of which the photo cathode 3 projects electrons at right angles thereto onto the target 9 through the wire screen I0. which vary according to the intensity of the light received by the diierent areas of the photo cathode in relation to the intensity of the light received through the respective color elements of the color mosaic 5. The impulses thus produced are transmitted by the aerial I6 and picked up by the receiving aerial I3 to be conveyed, with the aid of the circuits I9, to the picture tube 29 Where the electron scanning beam 22 scans the surface of the fluorescent material 2 I, thus forming light rays that pass through the color mosaic 23 located in a and the picture tube image,

correct or accurately adjusted position correspending exactly to the respective color elements of the color mosaic 5 in the camera tube 4. From time to time, if desired, the color screen 23 may be given any fine degrees of adjustment to make its position exactly accord with the scanning beam 22 and the elements of the color mosaic 5 in the camera tube. As the respective sets of monochrome colors of the two color mosaics 5 and 23 are at the same angle to the horizontal, a lateral adjustment of the color mosaic 23 will suffice for this purpose. In this Way, the televised subjects observed through the color mosaic screen 23 reproduce the colors received by the camera tube 2 without the need cf an intervening projection lens, although, of course, it will be understood that the image thus transmitted through the color mosaic screen 23 may be thrown onto any other or larger viewing screen or surface, if desired, by means of any desired projection system. In this Way, camera tubes and picture tubes, such as have been previously known, can be readily modied merely by applying thereto or using therewith c0101' mosaics or screens.

While I have described my invention above in detail, I wish it to be understood that many changes may be made Without departing from the spirit of the same. For instance, it will be understood that many other types of camera tubes or picture tubes or both may be used therewith. Furthermore, any other iuorescent materials producing white or colored light, as desired, may be utilized in the picture tubes. Also, any desired combination or set of color elements may be used with two or more colors in the color mosaics Ei and 23, and the color areas thereof may be of any desired shape or size. Also, the angles of the respective sets of monochrome colors in the 1 color mosaics 5 and 3 may be chosen or altered so as to be the same as the respective angles of the scanning electron beam lines, although it is preferable for the said angles to be diiferent, as pointed out above.

I claim:

A television picture tube apparatus l fluorescent surface in the tube and a si; Giona-ry color iilter comprising a plural color mosaic surface located outside said tube capable, While in a stationary position, of transmitting light in a succession of different colors from said uorescent surface, the plural color mosaic surface being in the form of a screen horizontally adinstable into a Xed position with regard to the picture tube, the plural color mosaic being in a geometrical pattern with the respective sequences of rectangular monochrome colors being located in lines inclined to substantially horizontal scanning beam lines.

ARTI-IUE?. WRIGHT.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 2,296,908 Crosby Sept. 29, 1942 2,389,979 Huinagle Nov. 27, 1945 2,452,293 De Forest Oct. 26, 1948 2,479,820 De Vore Aug. 23, 1949 2,480,848 Geer Sept. 6, 1949 2,493,200 Land Jan. 3, 1950 2,508,267 Kasperovvicz May 16, 1950 FOREIGN PATENTS Number Country Date .589,345 Great Britain Oct. 22, 1945 su; Nn, 

